Shyh-Jye Chen

Usefulness of Electron Beam Computed Tomography in Children With Heterotaxy Syndrome

Children with heterotaxy syndrome frequently have complex cardiac and noncardiac malformations requiring detailed diagnostic evaluation for management planning. Direct delineation of these structures by electron beam computed tomography (EBCT) is validated as a means of diagnosis. From July 1995 to March 1997, 32 patients (16 girls, 16 boys) with clinically impressed heterotaxy syndrome were enrolled in this study. After evaluation by echocardiography, EBCT studies were performed. Interpretation of cardiac anomalies was performed by sequential analysis based on these cross-sectional images. The diagnoses were subsequently confirmed by angiocardiography and surgical findings. Twenty-eight patients had bilateral trifurcated bronchi, and most of these (24 of 28) did not have a spleen. Four patients had bilateral bifurcated bronchi, 2 patients had polysplenia, and the other 2 patients had a lobulated single spleen. We found that laterality could be identified by EBCT in all patients. Comparison of diagnostic yield between echocardiography, catheterization, and EBCT showed that EBCT is superior to echocardiography and catheterization in demonstration of pulmonary venous anatomy and presence of a very small rudimentary ventricle. In addition, associated visceral, bronchopulmonary, mediastinal, and intracardiac anomalies could all be clearly delineated by EBCT at the same time. Thus, EBCT is a promising complementary modality for an overall understanding of heterotaxy syndrome.

A Study of Grid Artifacts Formation and Elimination in Computed Radiographic Images

Computed radiography (CR) has many advantages such as filmless operations, efficiency, and convenience. Furthermore, it is easier to integrate with the picture archiving and communication systems. Another important advantage is that CR images generally have a wider dynamic range than conventional screen film. Unfortunately, grid artifacts and moiré pattern artifacts may be present in CR images. These artifacts become a more serious problem when viewing CR images on a computer monitor when a clinic grade monitor is not available. Images produced using a grid with higher frequency or a Potter–Bucky grid (i.e., a moving grid, Bucky for short) can reduce occurrence but cannot guarantee elimination of these artifacts [CR & PACS (2000); Detrick F (2001), pp 7–8]. In this paper, the formation of the artifacts is studied. We show that the grid artifacts occur in a narrow band of frequency in the frequency domain. The frequency can be determined, accurately located, and thus removed from the frequency domain. When comparing the results obtained from the proposed method against the results obtained using previous computer methods, we show that our method can achieve better image quality.

Three-dimensional reconstruction of abnormal ventriculoarterial relationship by electron beam CT

PURPOSE Assessment of the relationships of the ventricles and great vessels is critical in evaluating cardiac anomalies before surgery. We investigated the usefulness of 3D CT in their demonstration. METHOD From July 1995 through June 1996, 20 patients with abnormal ventriculoarterial relationships were analyzed by electron beam CT. A 3D gradient shading surface rendering was done on a workstation. We focused on the morphologies of the atria, ventricles, and great vessels and particularly their spatial relationships on the 3D images. RESULTS There were two cases of isolated ventricular inversion, three of anatomically corrected malposition, seven of congenitally corrected transposition, and eight of complete transposition. Anatomic presentations of 3D surface images in all were superior to cineangiography and echocardiography presentations and were consistent with intraoperative findings. CONCLUSION 3D CT images provide useful information that is not available by sectional or projective imaging. Independent segmental analysis of the anomalies by this method provides a complement for surgeons to understand the spatial relationships of the vessels and chambers of the heart, which may be of value in preoperative planning.

Usefulness of three-dimensional electron beam computed tomography for evaluating tracheobronchial anomalies in children with congenital heart disease☆

This study was undertaken to delineate tracheobronchial anomalies associated with congenital heart disease. From June 1995 to December 2000, 1,245 children with congenital heart disease underwent cardiac electron beam computed tomography with 3-dimensional reconstruction on an independent workstation. Tracheobronchial anomalies are strongly associated with congenital heart disease and accompanying tracheal stenosis is not uncommon. With 3-dimensional reconstruction, electron beam computed tomography provided excellent anatomic definition of the central tracheobronchial abnormalities.

Retroesophageal aortic arch: diagnostic and therapeutic implications of a rare vascular ring

Retroesophageal aortic arch (REAA) can be further divided to right or left retroesophageal aortic arch. The right REAA has right ascending and left descending aorta with retroesophageal segment, whereas the left REAA has left ascending and right descending aorta. The REAA with retroesophageal segment may cause tracheoesophageal compression by the formation of a vascular ring. A total of eight patients were identified from the database from 1996 to 1999. Among them, five were right REAA and three were left REAA. The age at diagnosis varied from 4 days to 16 years (median 8 years). The clinical findings and initial diagnostic investigations, including the chest X-ray, echocardiography and esophagogram, suspected the presence of this anomaly. The diagnosis can be confirmed by ultrafast computed tomography with or without three-dimensional reconstruction. Half of the total patients, two of right and two of left REAA were symptomatic and needed operation. The symptoms related to the retroesophageal aortic arch appeared during infancy and early childhood (six cases), and only rarely in late childhood and adults (two cases). Half of the patients were associated with congenital heart disease, but no specific patterns of congenital heart disease were identified. The sensitivity of the early diagnosis of REAA by chest roentgenogram, echocardiography, esophagogram and angiography was 37% (3/8), 0% (0/7), 100% (1/1) and 60% (3/5), respectively. The sensitivity of ultrafast CT was 100% (8) in delineating both retroesophageal segment and complete vascular ring. Operation to relieve the vascular compression was performed in two cases with right REAA and two with left REAA. Only one died after the operation, due to pulmonary arterial sling and tracheal stenosis. The surviving patients had been asymptomatic during follow up. In conclusion, REAA can be best diagnosed by ultrafast computed tomography with or without three-dimensional reconstruction. If symptomatic, surgery to relieve the compression is effective and safe.

Accessory Left Atrial Appendage A Neglected Anomaly and Potential Cause of Embolic Stroke

A 69-year-old woman with a history of atypical chest pain was referred for coronary computed tomographic (CT) angiography study with a 64-detector row multidetector CT scanner (LightSpeed VCT, GE Healthcare, Milwaukee, Wis). Imaging was performed after multiphasic injection of nonionic contrast media (Omnipaque 350, GE Healthcare) into the right antecubital vein at a rate of 4.0 mL/s through a 20-gauge needle with a dual-barrel injector (Stellant D; Medrad, Warrendale, Pa). The coronary arteries were patent. However, a cauliflowerlike accessory atrial appendage was incidentally noted at the anterior roof of the left atrium (LA) (Figures 1 through 4). No definite thrombus was found inside this accessory atrial appendage. To further assess the contractility of this anomaly, volumetric measurements of the LA and appendages were performed. Twenty phases of CT images were reconstructed during the cardiac cycle. The maximum volume of the LA was 84.3 cm at 40% of cardiac cycle and the minimum volume was 67.3 cm at 0% of cardiac cycle. The fractional LA volume change was 20%. The maximum volume of the LA appendage was 7.1 cm and the minimum volume was 5.5 cm. The fractional LA appendage volume change was 32%. The volume of the accessory atrial appendage measured 1.0 cm, and in contrast to what was seen in the LA and LA appendage, no noticeable phasic change could be identified. Left atrial contour abnormalities are increasingly recognized with the improved spatial resolution of modern noninvasive imaging modalities. Focal outpouches of the LA have been reported to occur in 10% to 15% of the adult population.1,2 Thrombosis in the blind-ended small noncontractile accessory atrial appendage might be a possible source of unexplained embolic stroke. The clinical significance of this common but ignored condition will be elucidated in the near future with the growing clinical use of cardiac CT. Disclosures None.A 69-year-old woman with a history of atypical chest pain was referred for coronary computed tomographic (CT) angiography study with a 64-detector row multidetector CT scanner (LightSpeed VCT, GE Healthcare, Milwaukee, Wis). Imaging was performed after multiphasic injection of nonionic contrast media (Omnipaque 350, GE Healthcare) into the right antecubital vein at a rate of 4.0 mL/s through a 20-gauge needle with a dual-barrel injector (Stellant D; Medrad, Warrendale, Pa). The coronary arteries were patent. However, a cauliflower-like accessory atrial appendage was incidentally noted at the anterior …

Demonstration of extensive mesenteric venous thrombosis and intestinal infarction with multidetector row CT: value of curved planar reformations

We describe a case of extensive mesenteric venous thrombosis with small bowel infarction. Multidetector row computed tomography with curved planar reformation clearly demonstrated the full extents of the mesenteric venous thrombus and the infarcted bowel loops. The length of infarcted segment could be estimated from the curved planar reformatted image and correlated well with operative findings. To our knowledge, this is the first presentation and measurement of infarcted bowel loops on curved planar reformation.

Usefulness of 3D Reconstructed Computed Tomography Imaging for Double Outlet Right Ventricle

BACKGROUND/PURPOSE To evaluate the value of 3D reconstructed computed tomography (CT) imaging for patients with double outlet right ventricle (DORV). METHODS CT images were obtained preoperatively from 17 patients who ranged in age from 5 days to 5 years. Reconstructed 3D images were created using gradient-shading surface rendering, which allowed partial subtraction of the anterior sections of the virtual heart to view the interior. Interpretations of CT, echocardiography and cine-cardioangiography were compared and verified from surgical findings, autopsy, and consensus upon review of all imaging and diagnostic tests. RESULTS Three subaortic, seven subpulmonary, six non-committed, and one double-committed subtypes of ventricular septal defect (VSD) were observed. The 3D electron beam CT images provided good delineation of the spatial relationship inside the heart. The range of diagnostic accuracy for all VSD types in DORV was 88-100% for 3D CT, 71-94% for echocardiography, and 60-100% for cine-cardioangiography. In comparison, 3D CT offered better diagnostic accuracy for all variants of DORV. CONCLUSION 3D constructed CT imaging is a good modality for differentiating VSD type in DORV. It allowed us to directly evaluate the inside of cardiac chambers for the right ventricular outlet, great arterial root, and determine the VSD relationships.

Validation of pulmonary venous obstruction by electron beam computed tomography in children with congenital heart disease

The purpose of this study was to explore the useful imaging findings of electron beam computed tomography (EBCT) for diagnosing pulmonary venous obstruction (PVO) in children with congenital heart disease. From July 1995 to March 1998, 17 children (9 girls and 8 boys, aged 7 days to 14 years and 9 months [median 3 months]) with the diagnosis of PVO were enrolled in this study. All images were obtained by EBCT at the end-diastolic phase of the cardiac cycle after administration of intravenous iodinated contrast medium. The findings of 25 EBCT studies were retrospectively analyzed by 2 radiologists and were correlated with echocardiography, angiocardiography, and surgical findings. Main findings on EBCT for PVO were (1) structural narrowing, (2) thickened interlobular septa, (3) peribronchovascular cuffing, and (4) ground-glass opacity of the alveoli. Structural narrowing along the course of the pulmonary venous drainage was the most important finding in all examinations (25 of 25). Lung parenchymal changes secondary to PVO included thickened interlobular septa (17 of 25), peribronchovascular cuffing (15 of 25), and ground-glass opacity of the alveoli (8 of 25). Thus, the combination of these findings provides very useful data for the definitive diagnosis of PVO. Characteristic electron beam computed tomographic findings can validate suspected PVO noninvasively.

Right lung agenesis with left pulmonary artery sling

We report on a 2‐month‐old infant girl who had right pulmonary agenesis and an unusual course of the left pulmonary artery. Computed tomography and cardiac catheterization showed that the left pulmonary artery arose from the main pulmonary artery, crossing the midline, and reaching the left lung via an aberrant course between the esophagus and trachea. The coexistence of right pulmonary agenesis and left pulmonary sling is extremely rare. Unlike in other reports, our patient remained symptom‐free and in good health, with normal growth and development until age 2 years, when she died from complications during an attack of bronchiolitis caused by respiratory syncytial virus. Pediatr Pulmonol. 2000; 29:239–241.